1. Field of the Invention
The present invention relates to endoscopic surgical instruments, and more particularly relates to an endoscopic instrument having reciprocating jaw members which pivot in response to the opening and closing of a handle member, where the movement of the handles is translated through an elongated tubular body member to open and close the jaw mechanism.
The present invention further provides a device in which the jaw mechanism may comprise cutting scissor blades, a gripping device for holding tissue during surgery, holding surgical needles and the like. The device of the present invention may be provided with a rotatable tubular body for selectively positioning the angle at which the jaw mechanism operates, and provision is also made for the use of electrocautery capabilities to provide for cauterization at the surgical site.
2. Discussion of the Prior Art
In the prior art, various endoscopic surgical instruments are disclosed which utilize generally complex mechanisms for opening and closing handle members and jaw members to facilitate use of the device at a surgical site. Many devices provide an intricate construction in which a linkage mechanism for opening and closing the jaws requires numerous moving parts, while a sliding arrangement is provided between two extended rod members which activates the linkage mechanism in response to movement of the handle members. In addition, pivoting of the handle members in many cases causes an unwanted radial torquing force on the rod which requires additional space to be provided in the handle members to accommodate the radial movement of the rod.
Endoscopic devices presently in use include many devices having an interchangeable shaft assembly and jaw mechanism in which a common reusable handle may be used with a series of instruments. However, these devices suffer disadvantages in that the connecting mechanism oftentimes obstructs the view of the surgeon, and the integrity of the device may be decreased due to loosening of the connection. These disadvantages are critical due to the fact that an endoscopic surgical procedure requires precision instruments with tolerances that are carefully monitored. As the connections wear, precision is sacrificed, and the usefulness of the tool is diminished.
Greenberg, U.S. Pat. No. 4,674,501 discloses a surgical instrument having a pair of reciprocating shafts which are provided with a rotational indexing knob in which the shafts are allowed to rotate to position a cutting tool at a specific angle to the handles. The shafts slide on top of each other in response to opening and closing of the handle members to open and close the jaw members of the cutting instrument. The housing is secured to a stationary handle, such that the shaft assembly rotates with the indexing knob. One shaft is secured in a ball and socket joint to a movable handle which facilitates the sliding arrangement of the movable shaft over a stationary shaft. The handle assembly is disengagable from the housing by means of a screw, and the ball joint slides out of the socket to remove the handles. This type of device is subject to the disadvantage disclosed above, in which the integrity of the device is compromised due to the number of moving parts, as well as to the fact that the ball and socket joint is an inherently loose connection which will deteriorate during continued use.
Ger, U.S. Pat. No. 4,919,152, discloses a clip applying device having a stationary handle and a pivoting handle to which an elongated shaft arrangement is attached. At the end of the shaft is a pair of reciprocating jaw members which are operated in response to pivoting movement of the handles. An inner shaft member is attached to the pivoting handle, the shaft member passing through an outer tube member which is attached to the stationary handle. As the rod member passes through the stationary handle, as well as through the outer tube at the location it is attached to the stationary handle, radial movement of the rod within the outer tube must be accounted for since the rod is attached to the stationary handle at a non-movable point. In relation to this, the bushing member is necessary inside the stationary handle to accommodate the radial play in the rod member during opening and closing of the handles.
Straub et al., U.S. Pat. No. 4,590,936, discloses a microsurgical instrument having a complex gear mechanism for translating movement of the handles to an opening and closing movement of the jaw members. A helical slot is provided in a shaft member which allows a pin to move through the slot to move the jaw members. Furthermore, a ball and socket joint is provided in the movable handle to connect the movable handle to the inner rod.
Bauer, U.S. Pat. No. 4,128,099, discloses a forceps device having an attachment for cauterization which conducts current through the outer tube to the jaw mechanism. A complex insulation system is provided to insulate the handle from the shaft, as well as to insulate the shaft itself. This device suffers the disadvantage that in order to insulate the handle, the rod member is secured to an insulating bushing, and a second rod is provided to the bushing to connect to the handle members. Furthermore, the connection point for the electrical connector is positioned in an area which will obstruct the view of the surgeon as he looks down the device to a surgical site.
Endoscopic surgical instruments are known in the art which include cooperating cutting blade members. Typically, in such an instrument, a gap between the blade portions is evident when the blades are engaged for cutting. For some surgical procedures a gap between the blades is undesirable because it detrimentally affects cutting precision. Thus, the surgeon cannot achieve the clinical results desired, and in some cases, for example, ripping or tearing of tissue may occur.
Moreover, prior art endoscopic surgical instruments are known to suffer from undesirable splaying of the blade members. Normally, at least one blade member is movably attached to a pivot point. When the blade members are repeatedly used, or encounter a hard substance during use, the blade members will tend to move laterally apart from one another, or splay. Blade member splaying increases the gap between the blade surfaces, and detrimentally affects cutting ability and precision.
Further, an undesirable feature of prior art endoscopic surgical instruments occurs when the blade members extend past the desired closed position becoming "overstroked." To clarify, blade overstroke occurs when the blade surface of at least one movable blade member surpasses the desired closed cutting position of the reciprocating blade.
The novel endoscopic surgical instrument pursuant to the present invention obviates the disadvantages encountered in the prior art and provides a precise instrument which is easy to manufacture and efficient to use, which eliminates many of the moving parts required by prior art devices. The instrument of the present invention incorporates many features which are of use to the surgeon during an operation, while it maintains a lightweight construction in an easy to handle device in which all the features may be operated with one hand. Furthermore, the features are so positioned so as to provide a maximum line of sight for the surgeon without obstructing the view to the surgical site.